Percussion initiated rockets function on impact to perform a task in accordance with the design criteria.
In an earlier design, a percussion initiated spotting charge has been used as an explosive warhead on small practice rockets. One such explosive warhead includes a spotting head employing a stab primer for initiation of the spotting charge. In this device the firing pin, used to initiate the primer, is held off the primer prior to launch by a spring-weight arrangement. On acceleration, the weight with the hole in its center compresses the spring and locks to the firing pin with the tip end of the firing pin protruding through the weight. On deceleration, the springweight firing pin moves forward striking the primer and setting off the body charge. Such an arrangement has safety problems in handling prior to and during launch. Also, one disadvantage is that mechanical mechanisms tend to hang-up on deceleration and causes non-functioning on soft target. Hang-up also causes non-arming on acceleration as well. Therefore, it can be seen that there is a need for a device that has no moving parts, that is safe to operate and handle, and that is reliable in operation.
The need for a device with no moving parts was satisfied with an improved design disclosed in my prior U.S. Pat. No. 4,488,490 issued on Dec. 18, 1984 and assigned to the United States of America as represented by the Secretary of the Army, Washington, D.C. This assigned patent also provides detailed disclosures, including FIGS. 1, 2, and 3 which illustrate a view of a percussion initiated spotting charge at rest, a view of a percussion initiated spotting charge as it is being accelerated, and a view of a percussion initiated spotting charge which depicts the position of the various elements upon deceleration or target contact of the various elements
My improved device of U.S. Pat. No. 4,448,490 for use with a solid propellant rocket motor comprises a motor closure head having a percussion initiated spotting charge mounted on the motor closure head. The percussion initiated spotting charge in accordance with my earlier design includes a body made of a material sufficient for withstanding the acceleration forces and has a chamber with a pyrotechnic contained therein and said body has at one end thereof a lead material that is supported with a jacket material inside a front portion of the body structure and the lead structure has a percussion primer mounted at one end thereof and a chamber and hole communicates from the percussion primer to the pyrotechnic to cause the percussion primer to be communicated directly with the pyrotechnic and set the pyrotechnic charge off upon contacting a target.
A deficiency of my improved device, described hereinabove, has recently come to light wherein the deficiency was prevalent when environment of use included impacting with very soft targets such as soft earth or mud. In this environment an assist is needed to increase the performance of my earlier device by causing functioning on very soft targets.
Accordingly, it is an object of this invention to provide a percussion initiated spotting charge for a solid propellant rocket that has no moving parts and which additionally includes an attached member which causes functioning of the percussion initiated charge when the attached member impacts with very soft target such as mud or soft earth.
Another object of this invention is to provide a percussion initiating spotting charge in which each of the elements are made from relatively inexpensive materials but yet reliable, and wherein said attached member to initiate functioning on impacting with very soft targets is easily installed.
Still another object of this invention is to provide a relatively light and compact percussion initiated spotting charge having a spotting head member and an attached member which is in the form of an impactor-cap designed to form a contoured fit with the ogive of said spotting head.